The stop block installed at Melling was a solid concrete block with a limited ability to absorb impact forces. It was physically shifted in the first collision, and even further in the second. The second impact also split the concrete block near ground level and allowed it to rotate backward under the train. The train rode up and over the stop block as a consequence, sustaining substantial damage.
Modern shock-absorbing stop blocks used on other terminating train stations on the controlled network reduce the consequences in terms of injury to persons and damage to trains if overruns should occur that lead to trains striking the stop blocks.
The Commission recommends that KiwiRail replace the type of stop block that was in use at Melling with a new shock-absorbing type design that would be matched to the likely impact forces from a Matangi train.
